What are the basic research design issues? Describe them in some detail. Why is it important to consider basic design issues before conducting the study and even as early as at the time of...

What are the basic research design issues? Describe them in some detail. Why is it important to consider basic design issues before conducting the study and even as early as  at the time of formulationg the research question? Is a field study totally out of the question if one is trying to establish cause-and-effect relationships? An exploratory study is just as useful as a casual study. Discuss this statement. Why is the unit of analysis an integral part of the research design?